Depression is a disease that affects a large proportion of the population and is a result of multiple factors. According to the World Health Organization (WHO), depression ranks among the ten leading causes of disability and will become the second-largest cause of the global health burden by 2020. An estimated 121 million people worldwide suffer from a depressive disorder for which they require treatment. It is estimated that 5.8% of all men and 9.5% of all women will suffer from a depressive disorder in any given year and that 17% of all men and women will suffer from a depressive disorder at some point in their lives.
Several types of antidepressant medications are used to treat depressive disorders, such as selective serotonin reuptake inhibitors (SSRIs), tricyclics, and monoamine oxidase inhibitors (MAOIs). The SSRIs and other medications that affect neurotransmitters, such as dopamine and norepinephrine, generally have fewer side effects than tricyclics. However, studies report a potential link between antidepressant use and the emergence of suicidal tendencies. According to some studies suicidal ideation (SI) is an uncommon but potentially dangerous phenomenon that can emerge during antidepressant treatment. Although there is no clear understanding of the basis for the observed linkage, the Food and Drug Administration (FDA) issued a black box warning regarding the potential risk of worsening depression and/or emergence of suicidality (i.e., development of suicidal thoughts or behavior) in both adult and pediatric patients taking several antidepressants.
In view of the FDA's warning, there has been increasing hesitation by physicians to prescribe antidepressants, particularly to children and adolescents. The need exists for a method to identify individuals at risk for developing these dangerous side effects. The invention provides such a method that could provide information about a patient's susceptibility for treatment-emergent suicidal ideation (TESI). These and other objects and advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.